1.5 Network Topologies Protocols and Layers Flashcards
How are the nodes connected to one another in star topology?
All nodes indirectly connect to each other through one or more swithces
What type of topology do client-server models use?
Client-Server models
What are the advantages of a star topology?
If one node fails it doesn’t affect the other nodes
Have high performance due to fewer data collisions
New nodes can be quickly added
What are the disadvantages of a star network?
High maintainance
Expensive
The whole network fails if the switch fails as no node can communicate
How are nodes connected in a mesh network?
Connected to at least on other node through transmission media
What are the advantages of a Mesh Network?
Messages can be received quickly if the route is short
Messages have different routes to go through
New nodes can be added without interruption or interfering with other nodes
What are the disadvantages of a Mesh Network?
Many connections require high maintenance
Impractical as there is a lot of cables and connections
What is a protocol?
Set of rules of how devices communicate and transmit data across a network
What are MAC Addresses?
Unique piece of identities that every device has
Why is IP Address used?
Used when sending data between networks
They can be static or dynamic
What is the function of the TCP protocol?
Splits the data into packets and re-assembles
Provides error-free transmission between 2 routers
What is the function of the IP protocol?
Does the Packet switching
What is the function of the HTTP protocol?
Used for accessing websites
What is the function of the HTTPS protocol?
Secure version of HTTP
What is the function of the FTP protocol?
Moves files between devices
What is the function of the POP3 protocol?
Retrieves email from the server
Email is deleted on the server
What is the function of the IMAP protocol?
Retrieves email from the server
Email is kept on the server
What is the function of the SMTP protocol?
Sends emails
What is the function of layers?
They group similar protocols together which have similar function
What is the 1st step of packet switching?
Data is split into packets and numbered in orders
What is the 2nd step of packet switching?
Each packet is sent down the fastest route
What is the 3rd step of packet switching?
Packet numbers are put into order
What is the 4th step of packet switching?
If packets are missing timeout message is sent
What is the 5th step of packet switching?
Confirmation message is sent
What are the 4 layers?
Application layer - Encodes message
Transport layer - Breaks down the messages
Network layer - Adds the IP address
Datalink layer - Sends data over the physical network
What are the 4 layers?
Application layer - Encodes message
Transport layer - Breaks down the messages
Network layer - Adds the IP address
Datalink layer - Sends data over the physical network
Describe the differences between a URL and an IP address?
URL uses words/characters(eghttp://www.ocr.org.uk)
IP is numerical(eg.192.149.119.226)
URL needs converting (using DNS) to IP before it can be accessed
IP does not require conversion
What is one benefit of accessing the website using a URL rather than using an IP address?
Easier to remember
What is the role of a personal computer and a server in a client-server network?
Personal computer:
Sends requests to server
Shows results from server
Server:
Processes requests
Manages clients
Centrally stores files / software
Describe the task performed by the CU?
Provides timing signals
Provides control signals
What are the advantages of The Cloud?
Access any time
Access from anywhere
Access from any device
Automatic Backup
What is the internet?
Global collection of interconnected networks
What is a Domain Name Service?
In reality it is multiple domain name servers
What is hosting?
Websites are stored on servers dedicated for this purpose
What are the actions when the URL is converted into an IP address?
URL received by the DNS resolver server
Server then queries a DNS root name server
The root server responds with the address of the top-level domain server for .com
Resolver makes request to the .com TLD server
TLD responds with the IP address
Recursive solver sends a query to DNS
IP address is then return to the resolver
Then DNS resolver responds to the web browser with the IP address of the URL
What is latency caused by?
Bottlenecks in the infrastructure of the network
What affects the quality of copper cables?
Grade of copper
Insulating materials
What is a NIC?
The network interface controller connects a device to a wire of wireless networking connection
NIC uses a protocol to ensure successful communication
What is Ethernet?
A standard for networking technologies
Used for communicating on a wired local area network
Evaluated the uses of Wi-Fi
Easier to set up
Convenient
Can handle large number of users
Speeds slower than wired networks
The signal can be obstructed
Less secure than wired networks
Is bluetooth good?
Ideal for connecting personal devices
Very short range - only 10 meters
Very low power consumption compared to Wi-Fi
What are the 2 parts of an IPv4 address?
Network identifier
Host identifier
What is MAC addresses used for?
Route frames on a LAN
What are the features of an IPv4 address?
32 bits in size
Written as four numers
What are the features of an IPv6 address?
128 bits in size
Written as eight groups
What are the uses of standards?
Character set
What are standards used for?
Specified to hardware and software
Makes it possible for:
Manufactures and Producers do create products and services which are compatible with each other
What are the advantages of layering?
Reduces complexity of the program into manageable sub-problems
Devices can be manufactured to operate at particular layers
What is the transport layer responsible for?
Establishing an end-to-end connection
What is the purpose of the link layer?
Represents the actual physical connection between various network nodes
